As research on medical and biochemical research fields, especially gene therapy or genetic engineering, has made progress, mixing a very small amount of reagents has been increasingly required. Therefore, dispensing methods are required to be shifted from conventional syringe methods to methods in which a very small amount of droplets can be dispensed.
Furthermore, in the field of inkjet printers, there is a demand for high quality and high speed printing, so that the need for highly integrated inkjet heads having a narrow nozzle pitch has increased. Therefore, various droplet ejecting apparatuses having a micro-channel structure to which a micromachining technique such as LIGA process, etching and micro-pressing is applied have been devised and put to practice.
A molding resin material used for producing such an apparatus is required to have small shrinkage so that near-net-shape processing is possible, have flowability that allows molding a precise microscopic structure, and have chemical resistance.
However, at present, resins commonly used as molding resin material are thermoplastic resins, which have a large thermal expansion coefficient so that after injection forming, shrinkage occurs in the mold, and near-net-shape forming is not achieved. Therefore, in order to obtain a desired thermal expansion coefficient or shrinkage ratio, a method of adding inorganic fillers such as glass fibers to the resin was examined. However, when a resin composition containing inorganic fillers is used to mold a precision component, the precision component cannot be processed uniformly after the molding. In other words, since the hardness of the resin, which is the main component, is very different from that of the glass fibers which are the inorganic fillers, roughness tends to occur at the time of polishing. Furthermore, the maximum absorption wavelength of laser light of the resin is very different from that of the glass fibers, so that some portions are unprocessed during laser processing, and therefore precise finishing cannot be achieved.
Therefore, there is a need for a resin composition suitable for molding microscopic structures. That is, there is a need for a resin composition for molding having small shrinkage ratio, good mold transfer properties and excellent properties for post-processing such as polishing processing or laser processing.